AlxGa1-xN alloy is widely used in ultraviolet (UV) and deep-UV light emitters. One of the biggest challenges is the high resistivity and the difficulty to form good ohmic contact to high Al-fraction p-type AlxGa1-xN due to the poor p-type doping efficiency. Hexagonal boron nitride (h-BN) is an emerging material that has a large bandgap ((Eg ~ 6 eV)) and is feasible for p-type doping. It is also compatible to AlGaN material, thus is proposed to serve as p-type layer. In this talk, we report the deposition of the high deep-ultraviolet-transparent h-BN film on Al0.7Ga0.3N/sapphire templates by RF sputtering. The hexagonal phase of BN layer was confirmed by both Raman spectra and X-ray diffraction (XRD) measurements. The valence band offset at h-BN/Al0.7Ga0.3N heterointerface is determined to be almost near zero by X-ray photoelectron spectroscopy (XPS) measurement. The transmittance to 265nm deep-ultraviolet light is very high, almost near 100%. We also studied the electrical properties of Mg-doped h-BN. More details will be present at the conference.